1. Field of the Invention
This invention relates to a resin composition, and more particularly to a thermoplastic resin composition excellent in impact resistance comprising a polyphenylene ether resin and a polyarylene sulfide resin as its main constituent resin components.
2. Related Art
Although polyphenylene ether resin has excellent mechanical and electrical properties and a high heat resistance, it has a fault that it is inferior in moldability and solvent resistance. Accordingly, polyphenylene ether resin itself is greatly restricted in utilizability at the present time.
On the other hand, polyarylene sulfide resin exemplified by polyphenylene sulfide resin is one of the resins classified as heat-resistant resins. It is characterized by high continuous use temperature and high stiffness, and further by high melt fluidity, flame retardancy and excellent solvent resistance. Thus, it is widely used practically as molded articles and films. However, polyarylene sulfide resin has a fault that it is low in mechanical strengths and particularly in impact strength. This fault obstructs a further expansion of its use.
Under such a situation, it is industrially valuable to provide a resin composition simultaneously having the merits of polyphenylene ether resin and polyarylene sulfide resin, each having respective excellent characteristic feature, by blending them together, and a proposal has already been made for it (JP-B-56-34032). However, polyphenylene ether resin and polyarylene sulfide resin are generally poor in mutual affinity, and it is difficult at the present stage to obtain a resin composition of excellent mechanical properties by merely blending them.
In order to overcome such disadvantages, there have been proposed various resin compositions such as a resin composition comprising a polyphenylene ether resin, polyphenylene sulfide and an epoxy resin (JP-B-60-11063), a resin composition comprising a modified polyphenylene ether resin and polyphenylene sulfide (JP-A-64-36645), a resin composition comprising a modified polyphenylene ether resin, a modified polyphenylene sulfide and a binder (JP-A-1-266160), a resin composition comprising a modified polyphenylene ether resin, polyphenylene sulfide and a polyisocyanate compound (JP-A-2-49023), etc.
None of these compositions hitherto proposed, however, is satisfactory in impact resistance, though they are improved in solvent resistance and moldability.
The object of this invention is to provide a resin composition excellent in mechanical properties and particularly in impact strength which comprises, as its main resin constituents, a polyphenylene ether resin characterized by its excellent heat resistance and mechanical properties and a polyarylene sulfide resin characterized by its excellent solvent resistance, stiffness and melt fluidity.
With the aim of achieving the above-mentioned object, the present inventors conducted elaborated studies to find that, if a polyphenylene ether resin, a polyarylene sulfide resin and two or more kinds of specified organic compounds are melted and kneaded by a specified method, there can be obtained, surprisingly, a resin composition of which dispersion state is better and of which impact strength is much superior as compared with resin compositions prepared by melting and kneading these ingredients by other methods. Based on the finding, this invention was accomplished.
The resin composition of this invention thus obtained makes the best of its excellent impact strength and economicity and can be formed by various molding processes such as extrusion molding, injection molding, blow molding, etc., and thereby they can be supplied to the society as a variety of useful resin articles. Thus, this invention has a very high industrial value.